The Java drama continues this week as news of a new exploit for a previously unknown and unpatched flaw has surfaced. Malware writers are actively targeting the zero-day vulnerability.

According to researchers from security firm FireEye, which discovered the flaw Thursday, multiple customers have been attacked. Security analysts at the firm observed successful exploitation against browsers that have Java version 1.6 Update 41 and Java version 1.7 Update 15 installed.

"Not like other popular Java vulnerabilities in which security manager can be disabled easily, this vulnerability leads to arbitrary memory read and write in JVM process," a security bulletins reads. "After triggering the vulnerability, exploit is looking for the memory which holds JVM internal data structure like if security manager is enabled or not, and then overwrites the chunk of memory as zero."

Turn Off Java

If there's any saving grace, it may be poor engineering. FireEye reports the exploit is not very reliable. It tries to overwrite a big chunk of memory. As a result, the firm said, in most cases, upon exploitation, security analysts can still see the payload downloading. But it fails to execute and yields a JVM crash.

FireEye says it has notified Oracle about the in-the-wild discovery. Since this exploit affects the latest Java versions, FireEye urges users to disable Java in the browser until a patch has been released. Alternatively, FireEye recommended, set Java security settings to "high" and do not execute any unknown Java applets outside of the organization.

Wolfgang Kandek, CTO of Qualys, observed that the Java 7 update 15 was released just two weeks ago, yet security researchers already have found flaws in the software, plus now there is this latest news of exploits in the wild.

"These attacks are all against Java on the desktop and use the browser as an attack vector. Our recommendation is to uninstall Java from the desktop if possible, otherwise disconnect Java from the browser, which recent versions of Java have made much easier," Kandek told us.

"If neither of these options work look at a whitelisting solution for Java. Through its Zone mechanism, Internet Explorer enables you to disable Java in the Internet Zone, but to leave it enabled in the Trusted Sites zone, which then needs to contain the sites that you need to run Java on."

Exploiting Java Security

When Kandek said "security researchers," he meant more than one firm. Security Explorations also notified Oracle about a zero-day flaw in the latest version of Java. The Polish firm is concerned that flaws could be exploited to bypass Java's security sandbox and dump malware onto victim computers.

"So, many computer users find themselves in what is becoming a disturbingly familiar situation -- looking to see when Oracle will confirm that the flaws exist, and then waiting for the inevitable security update for Java," wrote Graham Cluley, a senior security analyst at Sophos.

"Many people who have Java enabled in their browser simply do not need it -- by the way, don't mix up Java with JavaScript; they're different things -- so the best solution for many folks is to rip Java out of their browser entirely."